The molecular mechanisms involved in DNA replication are not yet fully understood. We are using the in vitro apparatus composed of purified replication proteins coded by phage T4 to answer some of these questions. We plan to analyze the role of base pairing and base stacking interactions in the accuracy of replication using these enzymes. We also plan to identify, purify, clone and sequence the origin of T4 replication. Using these clones we plan to study interactions between the replication enzymes and features in DNA that are significant for initiation specificity. We shall also develop assays for genetic and biochemical recombination. Using these assays, the enzymes required for recombination shall be purified and used to develop an in vitro recombination system. Using such a system unknown functions involved in error prone recombinational repair will be identified and isolated.